Field of the Invention
The invention relates to an optical module and a display apparatus, and particularly relates to a light source module and a projection apparatus.
Description of Related Art
In recent years, projection apparatus that takes a laser diode as a solid state light source gradually occupies a place in the market. Besides capable of using a laser light emitted by a laser light source to excite a fluorescent powder to produce an excited light, the laser projection apparatus may also directly take the laser light as an illumination light source of the projection apparatus. In a structure of a general projection apparatus, a blue laser light excites the fluorescent powder adapted to convert the laser light into a green beam or a yellow beam on a fluorescence color wheel to produce the green beam or the yellow beam. The green beam passes through a green filter on a filter color wheel to produce a green beam meeting the requirement. A part of the yellow beam passes through a red filter to form a red beam, and a part of the yellow beam passes through a transparent area on the filter color wheel to form a yellow beam. Moreover, the blue beam passes through a hollow portion or a transparent area on the fluorescence color wheel and passes through the transparent area on the filter color wheel to form a blue beam.
Generally, in high definition television (HDTV) standard specifications specified by an international telecommunication union (ITU), Rec.709 is a basic image standard specification, which represents a standard color gamut. Requirement of a color gamut of DCI-P3 is wider, and color purity thereof is higher, and the current high class displays all take the color gamut of DCI-P3 as a color gamut target. A color gamut range of the projection apparatus is generally defined by coordinate points of the aforementioned blue beam, the green beam and the red beam in a CIE 1931 color space chroma diagram. The CIE 1931 color space is a color space defined by International Commission on Illumination (CIE) in 1931 by using a mathematical method. By comparing whether the color gamut range of the projection apparatus covers an area range of the specific standard color gamut in the CIE 1931 color space chroma diagram, it is learned whether a color presented by an image of the projection apparatus is complied with a specific color gamut specification. Conventionally, adjustment of the color space may adopt a Hue saturation and gain (HSG) adjustment method, where the Hue is different colors sensed by human eyes under illumination of lights of different wavelengths. Saturation refers to a purity of a color, and the higher the saturation is, the purer the color is, and the lower the saturation is, the more the color becomes gray. Gain refers to a brightness of a color. Therefore, color performance of a red color, a green color, a blue color, a yellow color, a blue green color and a magenta color projected by the projection apparatus are adjusted according to the HSG method.
The standard color gamut of a commonly used display or a projection apparatus is, for example, the Rec.709 standard color gamut or the DCI-P3 standard color gamut. However, a coordinate point of a blue beam provided by a commonly used blue laser light source of the projection apparatus in the CIE 1931 color space chroma diagram is slightly different to the coordinate point of the blue beam of the aforementioned commonly used standard color gamut specification. When a user views a blue image projected by such type of the projection apparatus, the user may feel that the image presents a slight blue purple color, which is not a standard blue color.
The information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Further, the information disclosed in the Background section does not mean that one or more problems to be resolved by one or more embodiments of the invention was acknowledged by a person of ordinary skill in the art.